[Qemu-devel] [PATCH v5 02/15] memory: Access MemoryRegion with MemOp

[<tony.nguyen@bt.com>]

Change memory_region_dispatch_{read|write} parameter "unsigned size"
to "MemOp op".

The endianness encoded in MemOp will enable the collapse of two byte
swaps, adjust_endianness and handle_bswap, along the I/O path.

Interfaces will be converted in two steps: first syntactically then
semantically.

The syntax change is usage of no-op MEMOP_SIZE and SIZE_MEMOP macros.
Being no-op there are no logical change, and we rely on coercion
between unsigned and MemOp.

The semantic change is implementing MEMOP_SIZE and SIZE_MEMOP to
logically convert an unsigned size to and from a size+sign+endianness
encoded MemOp.

Signed-off-by: Tony Nguyen <tony.nguyen@bt.com>
---
 include/exec/memop.h  | 4 ++++
 include/exec/memory.h | 9 +++++----
 memory.c              | 7 +++++--
 3 files changed, 14 insertions(+), 6 deletions(-)

diff --git a/include/exec/memop.h b/include/exec/memop.h
index ac58066..09c8d20 100644
--- a/include/exec/memop.h
+++ b/include/exec/memop.h
@@ -106,4 +106,8 @@ typedef enum MemOp {
     MO_SSIZE = MO_SIZE | MO_SIGN,
 } MemOp;

+/* No-op while memory_region_dispatch_[read|write] is converted to MemOp */
+#define MEMOP_SIZE(op)  (op)    /* MemOp to size.  */
+#define SIZE_MEMOP(ul)  (ul)    /* Size to MemOp.  */
+
 #endif
diff --git a/include/exec/memory.h b/include/exec/memory.h
index bb0961d..0ea4843 100644
--- a/include/exec/memory.h
+++ b/include/exec/memory.h
@@ -19,6 +19,7 @@
 #include "exec/cpu-common.h"
 #include "exec/hwaddr.h"
 #include "exec/memattrs.h"
+#include "exec/memop.h"
 #include "exec/ramlist.h"
 #include "qemu/queue.h"
 #include "qemu/int128.h"
@@ -1731,13 +1732,13 @@ void mtree_info(bool flatview, bool dispatch_tree, bool owner);
  * @mr: #MemoryRegion to access
  * @addr: address within that region
  * @pval: pointer to uint64_t which the data is written to
- * @size: size of the access in bytes
+ * @op: size of the access in bytes
  * @attrs: memory transaction attributes to use for the access
  */
 MemTxResult memory_region_dispatch_read(MemoryRegion *mr,
                                         hwaddr addr,
                                         uint64_t *pval,
-                                        unsigned size,
+                                        MemOp op,
                                         MemTxAttrs attrs);
 /**
  * memory_region_dispatch_write: perform a write directly to the specified
@@ -1746,13 +1747,13 @@ MemTxResult memory_region_dispatch_read(MemoryRegion *mr,
  * @mr: #MemoryRegion to access
  * @addr: address within that region
  * @data: data to write
- * @size: size of the access in bytes
+ * @op: size of the access in bytes
  * @attrs: memory transaction attributes to use for the access
  */
 MemTxResult memory_region_dispatch_write(MemoryRegion *mr,
                                          hwaddr addr,
                                          uint64_t data,
-                                         unsigned size,
+                                         MemOp op,
                                          MemTxAttrs attrs);

 /**
diff --git a/memory.c b/memory.c
index 5d8c9a9..6982e19 100644
--- a/memory.c
+++ b/memory.c
@@ -1439,10 +1439,11 @@ static MemTxResult memory_region_dispatch_read1(MemoryRegion *mr,
 MemTxResult memory_region_dispatch_read(MemoryRegion *mr,
                                         hwaddr addr,
                                         uint64_t *pval,
-                                        unsigned size,
+                                        MemOp op,
                                         MemTxAttrs attrs)
 {
     MemTxResult r;
+    unsigned size = MEMOP_SIZE(op);

     if (!memory_region_access_valid(mr, addr, size, false, attrs)) {
         *pval = unassigned_mem_read(mr, addr, size);
@@ -1483,9 +1484,11 @@ static bool memory_region_dispatch_write_eventfds(MemoryRegion *mr,
 MemTxResult memory_region_dispatch_write(MemoryRegion *mr,
                                          hwaddr addr,
                                          uint64_t data,
-                                         unsigned size,
+                                         MemOp op,
                                          MemTxAttrs attrs)
 {
+    unsigned size = MEMOP_SIZE(op);
+
     if (!memory_region_access_valid(mr, addr, size, true, attrs)) {
         unassigned_mem_write(mr, addr, data, size);
         return MEMTX_DECODE_ERROR;
--
1.8.3.1